Run "linters" once, with a single version of Python

[DimitriPapadopoulos]

Black is run multiple times, for each supported version of Python:

pip-licenses/.github/workflows/python-package.yml

Lines 15 to 31 in 6beaf9c

	strategy:
	matrix:
	python-version: ['3.9', '3.10', '3.11', '3.12', '3.13', '3.14']
	steps:
	- name: Checkout repository
	uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
	with:
	persist-credentials: false
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@e797f83bcb11b83ae66e0230d6156d7c80228e7c # v6.0.0
	with:
	python-version: ${{ matrix.python-version }}
	- name: Lint with black
	uses: psf/black@stable
	with:
	options: "--check --diff"

• This is not efficient, the version of Python used to run Black is irrelevant.
• The current version of Black requires Python 3.10, it cannot run under Python 3.9.

Same for MyPy.

Probably apply to branch dev-5.5.1 to fix CI in that branch.